Dishwashers are a frequently used household machine. The dirty items are placed in a washing chamber in which heated water is circulated in order to wash the different items in the dishwasher. The water is circulated in the washing chamber by a pumping device and sprayed on the dirty dish from a number of nozzles arranged on rotating arms in the washing chamber. The water flows downwards in the washing chamber and is passing through a filter system having a flat filter that is supported around its outer periphery by a supporting edge with a shape corresponding to the shape of the filter and secured in the intended position by a central filter unit, before it is collected in a sump in the lower section of the washing chamber and lead to the pump. Examples of different filter arrangements of the described type for dishwashers are known from EP1 340 448 and EP 1 424 034B1.
In order to provide the required filter area, the flat filter has a considerable size and the widely changing temperatures in the washing chamber in combination with the size and shape of the flat filter makes it difficult to ensure the desired sealing between the outer periphery of the filter and the supporting edge, especially since the filter regularly is removed for cleaning purpose. In case of dirty water bypassing the filter, the dirty water will continue to the pump and further to the water spray nozzles that in worst case get blocked by the particles in the water. Furthermore the filter arrangement is expensive to manufacture since the arrangement comprises several different components that must fit properly together to ensure the desired securing of the different filter arrangement components as well as the proper sealing between the different components.
There is consequently a need for an improved dishwasher that ensures that no dirty water is bypassing the filter.